Update devDependencies. (#29281)

Kept `eslint@6.1.0` since the newer versions have a bug that affects us.

package.json

@@ -112,14 +112,14 @@
     "clean-css-cli": "^4.3.0",
     "coveralls": "^3.0.6",
     "cross-env": "^5.2.0",
-    "eslint": "^6.1.0",
+    "eslint": "6.1.0",
     "eslint-config-xo": "^0.26.0",
     "eslint-plugin-import": "^2.18.2",
     "eslint-plugin-unicorn": "^10.0.0",
-    "find-unused-sass-variables": "^0.4.1",
+    "find-unused-sass-variables": "^0.4.2",
     "glob": "^7.1.4",
     "hammer-simulator": "0.0.1",
-    "hugo-bin": "^0.45.1",
+    "hugo-bin": "^0.45.2",
     "ip": "^1.1.5",
     "jasmine-core": "^3.4.0",
     "karma": "^4.2.0",
@@ -137,7 +137,7 @@
     "npm-run-all": "^4.1.5",
     "popper.js": "^1.15.0",
     "postcss-cli": "^6.1.3",
-    "rollup": "^1.19.4",
+    "rollup": "^1.20.1",
     "rollup-plugin-babel": "^4.3.3",
     "rollup-plugin-istanbul": "^2.0.1",
     "rollup-plugin-node-resolve": "^5.2.0",
@@ -146,7 +146,7 @@
     "shx": "^0.3.2",
     "stylelint": "^10.1.0",
     "stylelint-config-twbs-bootstrap": "^0.4.0",
-    "terser": "^4.1.4",
+    "terser": "^4.2.0",
     "vnu-jar": "19.6.7"
   },
   "engines": {